1. Field of the Invention
This invention relates to a robot laser processing system using an industrial robot.
2. Description of the Related Art
A laser processing system having an industrial robot with a processing nozzle mounted thereon, to emit a laser beam for automatically performing the desired laser processing work, is used in various areas including car assembly plants and printed circuit board production factories.
In this laser processing system, demand is high for a configuration in which a plurality of laser oscillators different in rated output can be connected to a robot and switched in accordance with the applications and situations of a production field, or a configuration in which a second laser oscillator is connected in addition to an laser oscillator used for normal processing process and, if the oscillator for normal processing process fails for some reason, the system is switched to the second laser oscillator.
A configuration in which a plurality of laser oscillators are connected to the robot and switched for actual use is required to meet two main conditions.
With reference to FIG. 6, an explanation will be given of a case in which a first laser oscillator is switched with a second laser oscillator.
In FIG. 6, a robot 102 controlled by a robot controller 140 includes a robot arm having a plurality of rotatably coupled arm members. A processing nozzle 104 mounted at the forward end of the robot 102 is connected to a laser oscillator 100-1 through an optical fiber 106. In FIG. 6, the laser oscillator 100-1 has four shutters 110-1, 112-1, 114-1, 116-1. FIG. 6 also shows another laser oscillator 100-2 which similarly has four shutters 110-2, 112-2, 114-2, 116-2.
In order to switch the laser oscillators, an operation to switch the connection of the optical fiber 106 is required first. As shown in FIG. 6, in the case where the laser oscillator 100-1 connected to the processing nozzle 104 of the robot 102 is switched to a different laser oscillator 100-2, the fiber 106 connected to the laser oscillator 100-1 is removed from the processing nozzle 104 of the robot 102 and the optical fiber 202 for the laser oscillator 100-2 is connected to the processing nozzle 104. As an alternative, as shown in FIG. 7, the optical fiber 106 for the laser oscillator 100-1 may be reconnected to the laser oscillator 100-2 without removing the fiber 106 from the processing nozzle 104.
This connecting job, though carried out manually in many cases, may be conducted using an optical fiber switching device as described in Japanese Unexamined Patent Publication No. 2001-259870.
In the cases shown in FIGS. 6 and 7, the laser oscillators 100-1, 100-2 use the first shutters 110-1, 110-2, respectively. In switching the oscillators, therefore, the shutter number command for the shutter which is opened when the processing operation need not be changed. In the case where the first shutter 110-1 is used for the laser oscillator 100-1 and the second shutter 112-2 is used for the laser oscillator 100-2 as shown in FIG. 8, however, the shutter number command must be changed when switching the laser oscillators.
After switching the optical fiber for the laser oscillator, the processing command from the robot must be transmitted to the laser oscillator after switching. The processing command from the robot, if currently transmitted to the laser oscillator 100-1, must be transmitted to the laser oscillator 100-2 after switching from the laser oscillator 100-1 to the laser oscillator 100-2.
FIGS. 9a, 9b are block diagrams showing a general configuration of the conventional robot laser processing system. As shown in FIG. 9a, in the conventional robot laser processing system, a host controller 120 (programmable logic controller, PLC) is directly connected with one robot controller 140 and a plurality of laser oscillators 100-1, 100-2, . . . , 100-n. Also, in the case of FIG. 9b having a plurality of robot controllers 140-1, 140-2, . . . , 140-n, the host controller 120 is connected directly with the plurality of the robot controllers 140-1, 140-2, . . . , 140-n and a plurality of laser oscillators 100-1, 100-2, . . . , 100-n. 
In the robot laser processing system shown in FIGS. 9a, 9b, the laser oscillator used by the robot under the control of the robot controller 140 is not selectively switched by an instruction from the host controller (PLC, etc.). The laser processing command from one robot controller 140 (or 140-1) is provisionally transmitted to the host controller 120, and then to the desired laser oscillator 100-1 (or 100-2) by the host controller 120. Specifically, this selective switching operation is performed by the host controller 120 changing the destination of the laser processing command. Also, the host controller 120 similarly changes the shutter number for the desired laser oscillator.
As described above, the host controller 120 is required to perform the control operation to switch the laser oscillator in addition to the normal line control operation and the robot control operation. As a result, the control operation in the host controller 120 is more complicated and leads to the problem that a considerable length of time is required to start the production line.
The fact that the laser processing command is sent through the host controller 120, on the other hand, causes loss of time and lengthens the cycle time.
Also, the host controller 120, while controlling the factory production line in general, on the one hand, is required to meet different specifications in accordance with different line configurations, on the other hand. In the case where the host controller 120 executes the operation of switching the laser oscillators as described above, therefore, the problem is posed that the internal processing of the host controller 120 is complicated and a considerable length of time is required each time the production line is started.
This invention is intended to solve these technical problems of the prior art, and the object thereof is to provide a robot laser processing system in which a processing command and a switching command can be sent directly to the laser oscillators from the robot controller without the intermediary of the host controller.